ALPHA CLUSTER STRUCTURE IN 13C AND
16,17OMarcia Regina Dias Rodrigues
Institute of Physics
University of São Paulo
W. von Oertzen, M. Freer, Y. Kanada-En’yo, Physics Reports 432, 43 (2006).K. Ikeda, N. Takigawa, and H. Horiuchi, Prog. Theor. Phys. Suppl. E68, 464 (1968); H. Horiuchi, K. Ikeda, and Y. Suzuki, ibid. 44, 225 (1978).
Alpha Cluster
19/04/2023 2NN2012 - M. R. D. Rodrigues
Microscopic a cluster model
Molecular model
a-particle gas like-states
-cluster phenomenon on light mass nuclei
Nuclear Spectroscopy with Light Ions Group
Investigation of a-clustering on (xa) and (xa + n) nuclei through (6Li,d) reaction.
Scarce experimental information on: – even-even nuclei resonant states near the thresholds.– odd-even nuclei .
Odd A nuclei:13C(6Li,d)17O and 9Be(6Li,d)13CEven A nuclei:12C(6Li,d)16O
19/04/2023 3NN2012 - M. R. D. Rodrigues
Experimental set up Pelletron-Enge-Spectrograph system 25.5 MeV 6Li beam Detection: nuclear emulsion
(Fuji G6B, 50 μm thick): covering 50 cm along the focal surface.
Target Thickness (g/cm2 )
9Be 13113C 9312C 112 / 52
19/04/2023 4NN2012 - M. R. D. Rodrigues
IFUSP-LAFNPelletron-Enge-Split-Pole-Spectograph facility
University of Sao Paulo – campus viewInstitute of Physics
19/04/2023 5NN2012 - M. R. D. Rodrigues
Pelletron-Enge-Split-Pole-Spectograph facility
Tandem 9MV
Maximum field 17 kG
Solid angle 2,68 msr
E max /E min 7.3
E/DE 275019/04/2023 6NN2012 - M. R. D. Rodrigues
19/04/2023 7NN2012 - M. R. D. Rodrigues
Pelletron-Enge-Split-Pole-Spectograph facility
Nuclear emulsion plates
No magnification(three spectra on each
emulsion plate)
View under 500x magnification(120x110m2)
819/04/2023 NN2012 - M. R. D. Rodrigues
Plates were scanned in strips of 200μm. Absolute cross section through elastic
scattering of 6Li on the same target.
Data
Reaction Energy resolution
(keV)
Dlab
(deg.)Number
of lab
DEexc (MeV)
9Be(6Li,d)13C 50 7º-20º 7 0-1513C(6Li,d)17O 50 5º-20º 5 0-1712C(6Li,d)16O 25 5º-29º 7 0-17
19/04/2023 9NN2012 - M. R. D. Rodrigues
0 10 20 30 40 500
100
200
300
400
5000 10 20 30 40 50
0
25
50
75
100
125
16
.71
8
16
.54
8
16
.47
81
6.3
2916
.05
4
15
.66
3
15
.48
7
15
.14
1
15
.04
6
14
.95
31
4.9
07
14
.68
8
14
.61
5
14
.43
2 14
.38
0
14
.32
61
4.2
03
14
.01
51
3.9
02
13
.86
91
3.7
40
/ 1
3.7
76
13
.61
513
.58
0
13
.31
3
13
.19
2
13
.09
4 /
13
.12
5
12
.84
2
12
.72
1
12
.65
5
12
.28
1
11
.93
8
11
.81
7
11
.12
7
10
.98
4
10
.49
81
0.4
10
10
.54
9
10
.35
0
10
.19
8 /
10
.22
7
L(cm)
9.8
10
10
.07
5
9.7
49
9.1
57
/ 9
.18
4
8.8
97
/ 8
.93
5
8.7
01
8.4
38
/ 8
.47
4
8.5
23
8.2
57
8.1
84
7.9
187.7
367.6
76
7.5
93
7.3
82
7.1
93 7
.21
9
6.9
72
6.8
53
6.1
97
5.8
71
/ 5
.93
9
G.S
.
Co
un
ts /
0.2
0 x
10
mm2
13C(6Li,d)17O E6Li= 25.5 MeV
Lab=110
3.8
40
4.5
48
3.0
53
0.8
71
5.2
30
5.1
22
5.6
95
/ 5
.73
5
α threshold
13C(6Li,d)17O
preliminary19/04/2023 10NN2012 - M. R. D. Rodrigues
0 10 20 30 40 500
100
200
300
400
500
Co
un
ts /
0.2
0 x
10
mm2
10
.82
6
9.8
91
10
.75
3
9.4
92
7.5
53
7.4
90
6.8
68
3.8
51
3.6
84
9Be(6Li,d)13C E6Li= 25.5 MeV
Lab=80
L(cm)
3.0
90
19/04/2023 11NN2012 - M. R. D. Rodrigues
9Be(6Li,d)13C ELi = 25.5 MeV , qLab= 5o
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19/04/2023 13NN2012 - M. R. D. Rodrigues
9Be(6Li,d)13C ELi = 25.5 MeV , qLab= 5o
19/04/2023 14NN2012 - M. R. D. Rodrigues
Preliminary Analysis
One step a transfer finite-range DWBA calculations.– Optical model in entrance and exit channels: global
parameters of Cook and Daehnick et al. – Binding potential (a+d) of Kubo and Hirata.– Resonant states assumed a bound by 100 keV in WS
potential (r0 = 1.25 fm, a = 0.65 fm). Relative to 9Be core for negative (G=4) and positive (G=5) parity a states were considered
J. Cook, Nucl. Phys. A388, 153 (1982) W.W. Daehnick, J.D. Childs and Z. Vrcelj, Phys. Rev. C 21, 2253 (1980)K.I. Kubo and M. Hirata, Nucl. Phys. A187, 186 (1972)
19/04/2023 15NN2012 - M. R. D. Rodrigues
19/04/2023 16NN2012 - M. R. D. Rodrigues
Resonances 7/2- at 10.753MeV and (5/2-) at 10.818MeV are now resolved and reached by an L = 4 transfer
Resonances 7/2- is also described using in the DWBA form factor the wave function obtained by a simplified calculation of the a+9Be system.
Local cluster – core potential, B. Buck, A.C.Merchant and S.M. Perez Phys. Rev. C51, 559 (1995)H. Miyake and M.A. Souza - IFUSP
a+ 9Be13C(inert core G.S.)
Resonance at 12.3 MeV, consistent with an L = 2 transfer, in agreement with 1/2- attribution of Kawabata - Strongly excited by (a,a’), present a large E0 transition.
19/04/2023 NN2012 - M. R. D. Rodrigues 17
12C(6Li,d)16O ELi = 25.5 MeV
Position deuteron spectrum and corresponding scattering angle. The Jp and excitation energies in MeV associated with each state from D. R. Tilley et al., Nucl. Phys. A 565 , 1-184 (1993) are indicated.
Position deuteron spectrum. Indicated is the region of the 4a threshold.
12C(6Li,d)16O reaction at 48.2MeV by A. Belhout et al., Nucl. Phys. A793, 178 (2007)
19/04/2023 18NN2012 - M. R. D. Rodrigues
12C(6Li,d)16O reaction at 42 MeV by C. Weldon et al.
Q3D deuteron spectrum at -21.5º
Q3D deuteron spectrum at -21.5º gated to select states decaying to the 12C ground state.
Q3D deuteron spectrum at -21.5º gated to select states decaying to the 12C 21
+ state at 4.439 MeV.
C. Wheldon et al., Phys. Rev. C 83, 064324 (2011).
19/04/2023 19NN2012 - M. R. D. Rodrigues
Elastic angular distribution and optical model predictions. The fitted parameters are rR = 1.70 fm and aR =0.66 fm.
19/04/2023 20NN2012 - M. R. D. Rodrigues
States with natural parities and indicated before as a direct process.
16O resonances in 12C(a,a0)12C (g.s.) excitation function.
L. L. Ames et al., Phys. Rev. C 25,729 (1982)
Experimental angular distributions not previously reported.
19/04/2023 21NN2012 - M. R. D. Rodrigues
Eexc (MeV) Jp Sa
14.62 4(+) 0.305(13)
14.66 5- 0.324(14)
14.81 (2+) 1.10(4)
14.81 6+ 1.27(6)
14.92 2+ 1.51(6)
19/04/2023 22NN2012 - M. R. D. Rodrigues
2- 4(-)
5+ 2-
C. Wheldon et al., Phys. Rev. C 83, 064324 (2011)
Ressonances decaying to 12C 21
+ state.
Experimental angular distributions not previously reported.
19/04/2023 23NN2012 - M. R. D. Rodrigues
K p =
K p =
K p =
Experimental alpha rotational bands on 16O.
was not seen
19/04/2023 24NN2012 - M. R. D. Rodrigues
Theoretical rotational band with a + 12C (0+2) cluster structure
S. Ohkubo and Y. Hirabayashi, Phys. Lett. B 684,127 (2010).
Next Steps Obtain detailed angular distributions and
complete the analysis of the data. Pursue the study of a-cluster states
populated through 13C(6Li,d)17O and 11B(6Li,d)15N reactions.
Extend structure calculation.
19/04/2023 25NN2012 - M. R. D. Rodrigues
Nuclear Spectroscopy with Light Ions, IFUSP, Brasil
Thereza Borello Lewin Marcia Regina Dias Rodrigues Hideaki Miyake José Luciano Miranda Duarte
Lighia Brighitta Horodynski Matsushigue Gilberto Mitsuo Ukita Cleber Lima Rodrigues Marco Antonio de Souza
MAGNEX Large-Aceptance Spectrometer, Laboratori Nazionali Sud, INFN, Catania, Italy
Angelo Cunsolo, Francesco CappuzzelloManuela CavallaroAntonino Foti
Clementina Agodi Diana Carbone
19/04/2023 26NN2012 - M. R. D. Rodrigues
19/04/2023 NN2012 - M. R. D. Rodrigues 27
Thanks
Obrigada